The invention relates to torque transmission devices, such as fixed, constant velocity ball joints as opposed track joints having
a joint external part having external tracks,
a joint internal part having internal tracks,
torque-transmitting balls, which are accommodated in track pairs made of external tracks and internal tracks,
a ball cage having cage windows, in which balls are retained and guided upon deflection of the joint,
first external tracks forming first track pairs, in which first balls are retained, with first internal tracks,
second external tracks forming second track pairs, in which second balls are retained, with second internal tracks,
the first track pairs and the second track pairs forming ball contact lines having opposing curvatures,
the external tracks and the internal tracks being delimited by external and internal track bases.
In practice, the ball raceways and/or running channels in opposed track joints as described, for example, in U.S. Pat. No. 6,872,143 (=DE 102 20 715) are produced by chip removal.
It has already been suggested in U.S. Pat. No. 7,396,284 (=DE 102 09 933) that the external tracks or running channels be formed in a chipless manner.
The chip-removing production according to U.S. Pat. No. 6,872,143 is primarily complex, and requires costly machines and long machining times. It also causes significant waste and quality losses in regard to the strength, because the material flow lines in a joint internal or external part produced as a preform by forging, are cut through by the machining.
To produce the ball raceways in joints such as those of '933 chipless, the prior art describes the possibility, for example, of providing hot-cold or warm-cold processes, a preform being produced within a forging procedure, for example, and the required precision being achieved in a cold calibration process.
Because it is an opposed track joint, differing tools each having opposing ball raceways must already be provided for the production of the preform for such a process. The precision of the parts is also limited by the guiding precision of the machine.
The unavoidable indexing irregularity in the preform also can no longer be remedied in the following machining steps.
A tool having the same irregularities is also required for the calibration process for each of the different ball raceways.